Pot chuck

ABSTRACT

A pot chuck for internal machining of hollow, thin walled, cylindrical objects includes a body having a cylindrical bore with a plurality of annular grooves provided in the surface of the bore. An elastomeric material fills the grooves and is bonded to the sides of the grooves. Passages in the chuck body form a means for introducing a pressurized fluid to the bottom of the grooves so that the elastomeric material will bulge and grip the object to be machined.

United States Patent 11 1 Hayes et a].

l l POT CHUCK 3,293,402 12/1966 Graham 279/4 x 2,720,735 10 1955 R hl l.279 4 X ,[75] Inventors: Ira Wade Hayes, Reinbeck; ue at a z g BarnesWaterloo Primary Erqminer-Gil Weidenfeld Attorney-H. VincentHarsha/William A. Murray [73] Assignee: Deere & Company, Moline, lll.,et

[22] Filed: May 8, 1972 [H571 B TR PP No.1 251,289 A pot chuck forinternal machining of hollow, thin walled, cylindrical objects includesa body having a cy- 521 U.S. c1 279/4, 279/1 Q, 269/22 hhdrieel herewith a plurality of annular grooves P 51 Int. Cl B23b 31/10 vided in theSurface f the hereeleetomerie mete- [58] Field 61 Search 279/4, 1 Q, 1s1, rial fills the grooves and is bonded to the Sides Of the 279/66;269/22 20 grooves. Passages in the chuck body form a means forintroducing a' pressurized fluid to the bottom of the [56] ReferencesCited grooves so that the elastomeric material will bulge and UNITEDSTATES PATENTS grip the object to be machined. 1 3,677,559 7/l972 Andreet al, 279/4 X 15 Claims, 2 Drawing Figures 20 /44\ 44\ 38 \e 1 1V lwfly 1 12V,

r 9! i! f 9! POT CHUCK BACKGROUND OF THE INVENTION The present inventionrelates generally to pot chucks, and more particularly relates to animproved low cost pot chuck for internal machining of hollow, thinwalled, cylindrical objects such as cylinder liners.

When gripping. thin walled, hollow, cylindrical objects such as cylinderliners for internal machining, it is necessary to grip with a sufficientforce to maintain the object substantially rigid with the chuck, butcare must be taken since the objects are easily deformed. This isgenerally accomplished by forming a pressure chamber with a yieldablematerial so that when pressurized, it will expand and grip the objectaround its entire perimeter. An example of one such chuck is illustratedin U. S. Pat. No. 2,720,735 issued to Ruehl et al on l8 Oct. 1955. Inthis chuck, the bore of the chuck was provided with a continuous spiralgroove and a one-piece hose of a yieldable material such as plastic waspositioned in the groove. Pressurization of the hose caused the hose toexpand so it gripped the object to be machined. This chuck had thecharacteristic of slowly releasing the object when pressure wasexhausted from the hose, and if the hose was damaged, the entire hosehad to be replaced resulting in high repair costs.

Another pot chuck used for internal machining of cylinder linersincluded a single bladder within the chuck bore which would expand whenpressurized-to grip the cylinder liner. The bladder, although it wouldtightly grip the cylinder liner, was somewhat spongy and would permit asmall amount of movement of the cylinder liner with respect to the chuckbody. Also, damage to a portion of the bladder required replace? ment ofthe entire bladder.

SUMMARY or THE INVENTION The principal object of the present inventionis to provide a pot chuck for internal machining of hollow, thin walled,cylindrical bodies such as cylinder liners which is of low initial cost,will hold the cylinder liners substantially rigid with the chuck body,has quick release characteristics, and is easily repaired in the eventof damage Another object of the present invention is to provide a potchuck for internal machining of hollow, thin walled, cylindrical bodieswhich includes a plurality of individual gripping elements which willengage the'hollow, thin walled, cylindrical object at spaced locationsalong the length thereof.

A furtherobject of the present invention is to provide a pot-chuck forgripping hollow, thin walled, cylindrical objects to be internallymachined which includes -a chuck body having an internal bore, aplurality of individual annular grooves provided in the surface of thebore, and elastomeric material filling each of the grooves and bonded tothe sides of the grooves, and a plurality of passages for introducing apressurized fluid to the bottom of each of the grooves so that theelastomeric material will bulge outwardly and grip the object to bemachined.

The above objects and additional objects and advantages of the presentinvention will become apparent to those skilled in the art from areading of the following detailed description when taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a cross-sectional view along the length of a pot chuckaccording to the present invention; and,

FIG. 2 is a sectional view of a portion of the pot chuck illustratingamodification of the pot chuck illustrated in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,and in particular to FIG. 1, the pot chuck according to the presentinvention includes a casing having a main body 10 and an end cap 12. Themain body 10 is generally of cylindrical shape, and is hollow to presenta cylindrical bore 14. The bore 14 is provided with enlarged areas 16and 18 at its two ends. The cap 12 is of annular shape, is slidablypositioned in the bore 14 and includes a radial flange 20 which isslidably received within the enlarged area 16 and abuts against the wallbetween the bore 14 and enlarged area 16 to properly position the cap12. The; cap 12 is secured tothe main body l0 in any suitable mannersuch as welding. I

A hollow cylindrical liner 22 is positioned within the bore 14 and isprovided with radially extending'flanges 24 and 26 which slidably engagethe walls of the bore 14 and enlarged area 18, respectively, to properlyposition the'liner within the main body 10. The liner 22 has an outerdiameter less than the diameter of the bore 14 so that the main body '10and liner 22 form an annular pressure chamber 28 which is closed at itsends by the flanges 24 and 26. The flange 24 is provided with an annulargroove 30 which receives an O-ring 32 providing a seal between theflange 24 and main body 10. The main body 10 is also provided with agroove 34 in the radial wall between the bore 14 and enlarged area 18which receives an O-ring 36 providing a seal between the flange 26 andmain body 10. The liner 22 is retained in a fixed position within thebore 14 by screws 38 which extend through the cap 12 and into the liner22.

The liner 22 is provided with a plurality of individual annular grooves40 which are spaced along the length of the liner 22. Each of thegrooves 40 is generally of dovetailed configuration in'cross section andis filled with an elastomeric material 42. The elastomeric material 42is bonded to the sides of each of the grooves 40 and is free from thebottom of each of the grooves 40 although normally in engagementtherewith. The outer surface of the elastomeric material in each of thegrooves 40 provides a gripping surface which isnormally substantiallyflush with the internal surface of the liner 22. I

A plurality of generally radial bones are provided in the liner 22 andextend through the liner 22 from the pressure chamber 28 to the bottomsof each of the grooves 40. Preferably, there are at least four equallyspaced bores 44 providing communication between each of the grooves 40and the pressure chamber 28.

A radial bore or passageway 46 extends through the main body 10 from theouter surface thereof to the pressure chamber 28 and is provided with athreadedouter end 48 adapted to receive a standard coupling on apressure line.

The operation of the above-described pot chuck should be obvious tothose skilled in the art, but is essentially as follows. The pot chuckis held in a conventional manner and a cylinder liner inserted into theright-hand end of the liner 22, the inside diameter of the liner 22 ofnecessity being just slightly greater than the outside diameter of thecylinder liner. Engagement between the cylinder liner and cap 12 willprevent the cylinder liner from being inserted too far into the liner22. With the cylinder liner positioned within the liner 22, a fluid,preferably air, under pressure is introduced to the pressure chamber 28through the bore 46. The pressurized fluid within the chamber 28 isrouted to the bottoms of the grooves 40 through the bores 44 and causesthe elastomeric material 42 to bulge outwardly so that its outer surfacemoves towards the axis of the liner 22 and grips the cyliner liner. Thisrigidly holds the cylinder liner so that it can be accurately machinedinternally.

When the cylinder liner has been properly machined, the pressure chamber28 is vented to atmosphere through the bore 46 so that the elastomericmaterial 42 returns to its original position as illustrated in FIG. 1and the cylinder liner can be removed.

The above-described pot chuck has avery low initial cost, has proved tohave a very quick release characteristic, and has such a good grippingcapability that the quality of work performed has been of better qualitythan the work performed with previous pot chucks. Also, damage to aportion of the elastomeric material only requires replacement of thematerial in one of the grooves and this substantially lowers repaircosts.

FIG. 2 illustrates a modified form of the pot chuck according to thepresent invention, and is, in all respects, similar to the pot chuckillustrated in FIG. 1 except for the configuration of the groovesprovided in the liner 22. In the embodiment illustrated in FIG. 2, thegrooves 40' are of T-shaped configuration in cross section. The T-shapedconfiguration of the grooves 40' makes it easier to bond the elastomericmaterial 42 to the walls of the groove without also bonding theelastomeric material to the bottom of the groove, and the T- shapedconfiguration also aids the bonding to hold the material within thegroove better than the dovetail configuration of the grooves in the FIG.1 embodiment.

Having thus described and illustrated two preferred embodiments of theinvention, various modifications within the spirit and scope of theinvention will become apparent to those skilled in the art and can bemade without departing from the underlying principles of the invention.Therefore, the invention should not be limited by the specificillustrations and descriptions, but only by the fair scope of thefollowing claims.

We claim:

1. A pot chuck for holding objects to be machined comprising: a casinghaving a cylindrical bore; a hollow cylindrical liner positioned withinthe casing bore and forming an annular pressure chamber therewith; aplurality of annular grooves provided in the internal surface of thelineryan elastomeric material filling the grooves and having outersurfaces normally substantially flush with the internal surface of theliner; a plurality of passageways provided through the liner from thepressure chamber to the grooves; and passage means provided in thecasing for introducing a fluid under pressure to the pressure chamberwhereby the elastomeric material will yield under the pressure and gripan object to be machined.

2. A pot chuck as set forth in claim 1 wherein the elastomeric materialis bonded to the sides of each of the grooves and is free from thebottom of each of the grooves although normally in engagement therewith.

3. A pot chuck as set forth in claim 1 wherein each of the grooves has agreater width at its bottom than at the internal surface of the linerwhereby the shape of the grooves serves to hold the elastomeric materialwithin the grooves.

4. A pot chuck as set forth in claim 3 wherein each of the grooves isgenerally of dovetailed cross-sectional configuration.

5. A pot chuck as set forth in claim 3 wherein each of the grooves isgenerally of T-shaped cross-sectional configuration.

6. A pot chuck as set forth in claim 3 wherein the elastomeric materialis bonded to the sides of each of the grooves and is free from thebottom of each of the grooves although normally in engagement therewith.

7. A pot chuck for holding thin walled, hollow, cylindrical objects tobe machined comprising: a chuck body having a cylindrical bore of adiameter slightly larger than the outside diameter of the cylindricalobject to be machined; a plurality of annular grooves provided in thesurface of the cylindrical bore in spaced positions from one end thereofto the other; elastomeric gripping material filling each of the groovesand having outer gripping surfaces normally substantially flush with thesurface of the bore; and passage means leading from the external surfaceof the body to each of the grooves for introducing a fluid underpressure to each of the grooves and the elastomeric material whereby theelastomeric material will yield and its outer gripping surfaces willmove outwardly of the grooves to grip the cylindrical object to bemachined.

8. A pot chuck as set forth in claim 7 wherein each of the grooves has agreater width at its bottom than at the surface of the bore whereby theshape of the grooves serves to hold the elastomeric material within thegrooves.

9. A pot chuck as set forth in claim 8 wherein the elastomeric materialis bonded to the sides of each of the grooves and is free from thebottom of each of the grooves although normally in engagement therewith.

10. A pot chuck as set forth in claim 9 wherein the passage means leadsto the bottom of each groove at a plurality of locations.

11. A pot chuck for holding hollow objects to be internally machinedcomprising: a casing having a cylindrical bore; a hollow cylindricalliner member positioned in the casing bore, having an outside diameterless than the diameter of the case, and including an annular outwardlyextending flange at each end thereof of a size to just fit within thecasing bore; seal means between each of the'fianges and the casingwhereby the casing and liner form an annular pressure chamber betweenthe flanges; a plurality of internal annular grooves provided in theliner; a plurality of generally radially extending passageways extendingbetween each of the grooves and the pressure chamber; an elastomericmaterial filling each of the grooves and having outer gripping surfacesnormally substantially flush with the internal surface of the liner; andmeans for introducing a fluid under pressure to the pressure chamberwhereby the elastomeric material will yield under the pressure and itsouter gripping surfaces will move groove and is free from the bottom ofeach groove although normally in engagement therewith.

14. A pot chuck as set forth in claim 13 wherein each of the grooves isgenerally of T-shaped cross-sectional configuration.

15. A pot chuck as set forth in claim 13 wherein each of the grooves isgenerally of dovetailed cross-sectional configuration.

1. A pot chuck for holding objects to be machined comprising: a casinghaving a cylindrical bore; a hollow cylindrical liner positioned withinthe casing bore and forming an annular pressure chamber therewith; aplurality of annular grooves provided in the internal surface of theliner; an elastomeric material filling the grooves and having outersurfaces normally substantially flush with the internal surface of theliner; a plurality of passageways provided through the liner from thepressure chamber to the grooves; and passage means provided in thecasing for introducing a fluid under pressure to the pressure chamberwhereby the elastomeric material will yield under the pressure and gripan object to be machined.
 2. A pot chuck as set forth in claim 1 whereinthe elastomeric material is bonded to the sides of each of the groovesand is free from the bottom of each of the grooves although normally inengagement therewith.
 3. A pot chuck as set forth in claim 1 whereineach of the grooves has a greater width at its bottom than at theinternal surface of the liner whereby the shape of the grooves serves tohold the elastomeric material within the grooves.
 4. A pot chuck as setforth in claim 3 wherein each of the grooves is generally of dovetailedcross-sectional configuration.
 5. A pot chuck as set forth in claim 3wherein each of the grooves is generally of T-shaped cross-sectionalconfiguration.
 6. A pot chuck as set forth in claim 3 wherein theelastomeric material is bonded to the sides of each of the grooves andis free from the bottom of each of the grooves although normally inengagement therewith.
 7. A pot chuck for holding thin walled, hollow,cylindrical objects to be machined comprising: a chuck body having acylindrical bore of a diameter slightly larger than the outside diameterof the cylindrical object to be machined; a plurality of annular groovesprovided in the surface of the cylindrical bore in spaced positions fromone end thereof to the other; elastomeric gripping material filling eachof the grooves and having outer gripping surfaces normally substantiallyflush with the surface of the bore; and passage means leading from theexternal surface of the body to each of the grooves for introducing afluid under pressure to each of the grooves and the elastomeric materialwhereby the elastomeric material will yield and its outer grippingsurfaces will move outwardly of the grooves to grip the cylindricalobject to be machined.
 8. A pot chuck as set forth in claim 7 whereineach of the grooves has a greater width at its bottom than at thesurface of the bore whereby the shape of the grooves serves to hold theelastomeric material within the grooves.
 9. A pot chuck as set forth inclaim 8 wherein the elastomeric material is bonded to the sides of eachof the grooves and is free from the bottom of each of the groovesalthough normally in engagement therewith.
 10. A pot chuck as set forthin claim 9 wherein the passage means leads to the bottom of each grooveat a plurality of locations.
 11. A pot chuck for holding hollow objectsto be internally machined comprising: a casing having a cylindricalbore; a hollow cylindrical liner member positioned in the casing bore,having an outside diameter less than the diameter of the case, andincluding an annular outwardly extending flange at each end thereof of asize to just fit within the casing bore; seal means between each of theflanges and the casing whereby the casing and liner form an annularpressure chamber between the flanges; a plurality of internal annulargrooves provided in the liner; a plurality of generally radiallyextending passageways extending between each of the grooves and thepressure chamber; an elastomeric material filling each of the groovesand having outer gripping surfaces normally substantially flush with theinternal surface of the liner; and means for introducing a fluid underpressure to the pressure chamber whereby the elastomeric material willyield under the pressure and its outer gripping surfaces will moveoutwardly of the grooves to grip the object to be machined.
 12. A potchuck as set forth in claim 11 wherein each of the grooves has a greaterwidth at its bottom than at the internal surface of the liner wherebythe shape of the grooves retains the elastomeric material within thegrooves.
 13. A pot chuck as set forth in claim 12 wherein theelastomeric material is bonded to the sides of each groove and is freefrom the bottom of each groove although normally in engagementtherewith.
 14. A pot chuck as set forth in claim 13 wherein each of thegrooves is generally of T-shaped cross-sectional configuration.
 15. Apot chuck as set forth in claim 13 wherein each of the grooves isgenerally of dovetailed cross-sectional configuration.